Power and resource efficient appdu based approach with scheduled data transmission times for wlan

ABSTRACT

Disclosed are methods and apparatuses for communications by which a physical layer packet is generated for transmission to a node, or by which a physical layer packet is received from a node, the physical layer packet having a plurality of MAC packets, wherein the physical layer packet includes a transmission schedule associated with the plurality of MAC packets in the physical layer packet.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

The present Application for Patent claims priority to ProvisionalApplication No. 61/090,521 entitled “A POWER AND RESOURCE EFFICIENTAPPDU BASED APPROACH WITH SCHEDULED BLOCK ACKS FOR WLAN” filed Aug. 20,2008, and assigned to the assignee hereof and hereby expresslyincorporated by reference herein.

BACKGROUND

I. Field

The following description relates generally to communication systems,and more particularly to power and resource efficiency in a wirelessnetwork.

II. Background

In order to address the issue of increasing bandwidth requirements thatare demanded for wireless communications systems, different schemes arebeing developed to allow multiple user terminals to communicate with asingle access point by sharing the channel resources while achievinghigh data throughputs. Multiple Input or Multiple Output (MIMO)technology represents one such approach that has recently emerged as apopular technique for the next generation communication systems. MIMOtechnology has been adopted in several emerging wireless communicationsstandards such as the Institute of Electrical Engineers (IEEE) 802.11standard. IEEE 802.11 denotes a set of Wireless Local Area Network(WLAN) air interface standards developed by the IEEE 802.11 committeefor short-range communications (e.g., tens of meters to a few hundredmeters).

MIMO technology holds great promise for wireless communication systemsof the future. However, there is still a need to further increase datathroughput within MIMO applications, as well as other communicationtechnologies.

SUMMARY

In one aspect of the disclosure, an apparatus includes a processingsystem configured to generate a physical layer packet for transmissionto a node, the physical layer packet having a plurality of MAC packets,wherein the physical layer packet includes a transmission scheduleassociated with the plurality of MAC packets in the physical layerpacket.

In another aspect of the disclosure, an apparatus includes a processingsystem configured to receive a physical layer packet from a node, thephysical layer packet having a plurality of MAC packets, wherein thephysical layer packet includes a transmission schedule associated withthe plurality of MAC packets in the physical layer packet.

In yet another aspect of the disclosure, a method of communicationincludes generating a physical layer packet for transmission to a node,the physical layer packet having a plurality of MAC packets, wherein thephysical layer packet includes a transmission schedule associated withthe plurality of MAC packets in the physical layer packet.

In yet another aspect of the disclosure, a method of communicationincludes receiving a physical layer packet from a node, the physicallayer packet having a plurality of MAC packets, wherein the physicallayer packet includes a transmission schedule associated with theplurality of MAC packets in the physical layer packet.

In another aspect of the disclosure, an apparatus for communicationincludes means for generating a physical layer packet for transmissionto a node; and means for providing a plurality of MAC packets in thephysical layer packet; wherein the physical layer packet includes atransmission schedule associated with the plurality of MAC packets inthe physical layer packet.

In another aspect of the disclosure, an apparatus for communicationincludes means for receiving a physical layer packet from a node; andmeans for providing a plurality of MAC packets in the physical layerpacket; wherein the physical layer packet includes a transmissionschedule associated with the plurality of MAC packets in the physicallayer packet.

In yet another aspect of the disclosure, a computer-program product forcommunication includes a machine-readable medium encoded withinstructions executable to: generate a physical layer packet fortransmission to a node, the physical layer packet having a plurality ofMAC packets, wherein the physical layer packet includes a transmissionschedule associated with the plurality of MAC packets in the physicallayer packet.

In still another aspect of the disclosure, a computer-program productfor communication includes a machine-readable medium encoded withinstructions executable to: receive a physical layer packet from a node,the physical layer packet having a plurality of MAC packets, wherein thephysical layer packet includes a transmission schedule associated withthe plurality of MAC packets in the physical layer packet.

In another aspect of the disclosure, an access point includes aprocessing system configured to generate a physical layer packet fortransmission to a node, the physical layer packet having a plurality ofMAC packets, wherein the physical layer packet includes a transmissionschedule associated with the plurality of MAC packets in the physicallayer packet; and a wireless network adapter configured to support abackhaul connection for a peer node to a network.

In another aspect of the disclosure, an access terminal includes aprocessing system configured to receive a physical layer packet from anode, the physical layer packet having a plurality of MAC packets,wherein the physical layer packet includes a transmission scheduleassociated with the plurality of MAC packets in the physical layerpacket; and a user interface supported by the processing system.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other sample aspects of the invention will be described in thedetailed description that follow, and in the accompanying drawings,wherein:

FIG. 1 is a diagram of a wireless communications network;

FIG. 2 illustrates frame aggregation in MAC and PHY layers of a wirelessnode in the wireless communications network of FIG. 1;

FIG. 3 illustrates an example of aggregated data transmission withscheduled block acknowledgements;

FIG. 4 illustrates a DTT payload in a segment of a wireless node in thewireless communications network of FIG. 1;

FIG. 5 is a block diagram of an example of signal processing functionsof a PHY layer of a wireless node in the wireless communications networkof FIG. 1;

FIG. 6 is a block diagram illustrating an exemplary hardwareconfiguration for a processing system in a wireless node in the wirelesscommunications network of FIG. 1;

FIGS. 7 and 8 are flow charts illustrating functionality of softwaremodules with respect to various aspects disclosed in FIGS. 2-6;

FIG. 9 is a block diagram illustrating an example of the functionalityof an apparatus for communication according to an embodiment of theinvention; and

FIG. 10 is a block diagram illustrating an example of the functionalityof an apparatus for communication 1000 according to another embodimentof the invention.

In accordance with common practice, some of the drawings may besimplified for clarity. Thus, the drawings may not depict all of thecomponents of a given apparatus (e.g., device) or method. Finally, likereference numerals may be used to denote like features throughout thespecification and figures.

DETAILED DESCRIPTION

Various aspects of the invention are described more fully hereinafterwith reference to the accompanying drawings. This invention may,however, be embodied in many different forms and should not be construedas limited to any specific structure or function presented throughoutthis disclosure. Rather, these aspects are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the invention to those skilled in the art. Based on theteachings herein one skilled in the art should appreciate that that thescope of the invention is intended to cover any aspect of the inventiondisclosed herein, whether implemented independently of or combined withany other aspect of the invention. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the invention is intended tocover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the invention set forth herein. Itshould be understood that any aspect of the invention disclosed hereinmay be embodied by one or more elements of a claim.

Several aspects of a wireless network will now be presented withreference to FIG. 1. The wireless network 100 is shown with severalwireless nodes, generally designated as nodes 110 and 120. Each wirelessnode is capable of receiving and/or transmitting. In the discussion thatfollows the term “receiving node” may be used to refer to a node that isreceiving and the term “transmitting node” may be used to refer to anode that is transmitting. Such a reference does not imply that the nodeis incapable of performing both transmit and receive operations.

In the detailed description that follows, the term “access point” isused to designate a transmitting node and the term “access terminal” isused to designate a receiving node for downlink communications, whereasthe term “access point” is used to designate a receiving node and theterm “access terminal” is used to designate a transmitting node foruplink communications. However, those skilled in the art will readilyunderstand that other terminology or nomenclature may be used for anaccess point and/or access terminal. By way of example, an access pointmay be referred to as a base station, a base transceiver station, astation, a terminal, a node, an access terminal acting as an accesspoint, or some other suitable terminology. An access terminal may bereferred to as a user terminal, a mobile station, a subscriber station,a station, a wireless device, a terminal, a node, or some other suitableterminology. The various concepts described throughout this disclosureare intended to apply to all suitable wireless nodes regardless of theirspecific nomenclature.

The wireless network 100 may support any number of access pointsdistributed throughout a geographic region to provide coverage foraccess terminals 120. A system controller 130 may be used to providecoordination and control of the access points, as well as access toother networks (e.g., Internet) for the access terminals 120. Forsimplicity, one access point 110 is shown. An access point is generallya fixed terminal that provides backhaul services to access terminals inthe geographic region of coverage; however, the access point may bemobile in some applications. An access terminal, which may be fixed ormobile, utilizes the backhaul services of an access point or engages inpeer-to-peer communications with other access terminals. Examples ofaccess terminals include a telephone (e.g., cellular telephone), alaptop computer, a desktop computer, a Personal Digital Assistant (PDA),a digital audio player (e.g., MP3 player), a camera, a game console, orany other suitable wireless node.

The wireless network 100 may support MIMO technology. Using MIMOtechnology, an access point 110 may communicate with multiple accessterminals 120 simultaneously using Spatial Division Multiple Access(SDMA). SDMA is a multiple access scheme which enables multiple streamstransmitted to different receivers at the same time to share the samefrequency channel and, as a result, provide higher user capacity. Thisis achieved by spatially preceding each data stream on the downlink. Thespatially precoded data streams arrive at the access terminals withdifferent spatial signatures, which enable each access terminal 120 torecover the data stream destined for that access terminal 120. On theuplink, each access terminal 120 transmits a spatially precoded datastream, which enables the access point 110 to identify the source ofeach spatially precoded data stream.

One or more access terminals 120 may be equipped with multiple antennasto enable certain functionality. With this configuration, multipleantennas at the access point 110 may be used to communicate with amultiple antenna access terminal to improve data throughput withoutadditional bandwidth or transmit power. This may be achieved bysplitting a high data rate signal at the transmitter into multiple lowerrate data streams with different spatial signatures, thus enabling thereceiver to separate these streams into multiple channels and properlycombine the streams to recover the high rate data signal.

While portions of the following disclosure will describe accessterminals that also support MIMO technology, the access point 110 mayalso be configured to support access terminals that do not support MIMOtechnology. This approach may allow older versions of access terminals(i.e., “legacy” terminals) to remain deployed in a wireless network,extending their useful lifetime, while allowing newer MIMO accessterminals to be introduced as appropriate.

In the detailed description that follows, various aspects of theinvention will be described with reference to a MIMO system supportingany suitable wireless technology, such as Orthogonal Frequency DivisionMultiplexing (OFDM). OFDM is a technique that distributes data over anumber of subcarriers spaced apart at precise frequencies. The spacingprovides “orthogonality” that enables a receiver to recover the datafrom the subcarriers. An OFDM system may implement IEEE 802.11, or someother air interface standard. Other suitable wireless technologiesinclude, by way of example, Code Division Multiple Access (CDMA), TimeDivision Multiple Access (TDMA), or any other suitable wirelesstechnology, or any combination of suitable wireless technologies. A CDMAsystem may implement with IS-2000, IS-95, IS-856, Wideband-CDMA (WCDMA),or some other suitable air interface standard. A TDMA system mayimplement Global System for Mobile Communications (GSM) or some othersuitable air interface standard. As those skilled in the art willreadily appreciate, the various aspects of this invention are notlimited to any particular wireless technology and/or air interfacestandard.

A wireless node, whether an access point (AP) or access terminal (AT),may be implemented with a protocol that utilizes a layered structure. Byway of example, as shown in FIG. 2, a layered structure may include anapplication layer 202, a Medium Access Control layer (MAC) 204 and aphysical layer (PHY) 206. The physical layer 206 implements all thephysical and electrical specifications to interface the wireless node tothe shared wireless channel. The MAC layer 204 coordinates access to theshared wireless channel and is used to interface higher layers, such asthe application layer 202, to the physical layer 206. The applicationlayer 202 performs various data processing functions including, by wayof example, speech and multimedia codecs and graphics processing.Additional protocol layers (e.g., network layer, transport layer) may berequired for any particular application. In some configurations, thewireless node may act as a relay point between an access point and anaccess terminal, or two access terminals, and therefore, may not requirean application layer. Those skilled in the art will be readily able toimplement the appropriate protocol for any wireless node depending onthe particular application and the overall design constraints imposed onthe overall system. The term “data packet” as used herein is to beconstrued broadly as any of a MAC packet, an aggregate MAC packet(described below), a physical layer payload (also described below), apacket received from the application layer, fragments and/orcombinations of other packets, a frame, packet, timeslot, segment, orany other suitable nomenclature.

When the wireless node is in a transmit mode, the application layer 202processes data, segments the data into packets 208, and provides thedata packets 208 to the MAC layer 204. The MAC layer 204 assembles MACpackets 210 with each data packet 208 from the application layer 202being carried by the payload 212 of a MAC packet 210. Each MAC packet210 includes a MAC header 214 appended to the payload 212. The MACpacket 210 is sometimes referred to as a MAC Protocol Data Unit (MPDU),but may also be referred to as a frame, packet, timeslot, segment, orany other suitable nomenclature. Although FIG. 2 shows one applicationlayer data packet 208 per MAC packet 210, it is also possible toincorporate multiple application layer data packets into the payload ofone MAC packet. Alternatively, multiple application layer data packetsmay be fragmented and distributed over more than one MAC packet.

Multiple MAC packets 210 having a same destination address may becombined into one aggregate MAC packet 216. An aggregate MAC packet 216is sometimes referred to as an aggregate MAC protocol data unit (AMPDU).Each MAC packet 210 in the aggregate MAC packet 216 is appended with asubframe header 218. A MAC packet appended with a subframe header asshown in FIG. 2 is referred to herein simply as a subframe 220. Theaggregate MAC packet 216 may be made up of several such subframes 220.Each subframe header 218 may include a length field 219, error detection222, and a delimiter signature 224. The beginning and end of eachsubframe 220 may be determined by the length field 219 and delimitersignature 224. The error detection may comprise a cyclic redundancycheck, a checksum, or any other suitable error detection code thatenables verification of respective subframes 220 independently.MAC-level frame aggregation as described above allows for the removal ofspaces between MAC packets (inter-frame spaces) as well as the removalof redundancies in the MAC headers (header compression). For example, ifeach MAC packet 210 in an aggregate MAC packet 216 is to be transmittedto the same receiving node, the destination address may be eliminatedfrom the MAC headers 214 of the subframes 220 following the firstsubframe in the aggregate MAC packet 216.

Although FIG. 2 shows one MAC packet per subframe, each subframe mayinclude more than one MAC packet. Alternatively, multiple MAC packetsmay be fragmented and distributed over more than one subframe. In somecases, although the subframes 220 in the aggregate MAC packet 216 are tobe transmitted to the same receiving node, they are not required to havethe same source address.

When the MAC layer 204 decides to transmit, it provides the aggregateMAC packet 216 to the PHY layer 206. The PHY layer assembles a PHYpacket 226 by appending a preamble (sometimes referred to as a PhysicalLayer Convergence Protocol (PLCP)) 228 and a header 230 to the payload232 carrying the aggregate MAC packet. The PHY packet is sometimesreferred to as a Physical Layer Protocol Data Unit (PPDU), but may alsobe referred to as a frame, packet, timeslot, segment, or any othersuitable nomenclature. The preamble may include at least one ShortTraining Field (STF) 234 and at least one Long Training Field (LTF) 236.The STF and LTF may be used by a receiving node for detecting the startof the PHY packet 226, synchronizing to the transmitter's node dataclock, performing channel estimation, calculating the AGC gain, and insome cases, estimating spatial streams in networks supporting MIMOtechnology. The header 230 may include a Signal Field (SIG) 238. The SIGfield 238 may include information regarding the data rate and length ofthe payload 232.

The PHY packet 226 shown in FIG. 2 may be assembled into an aggregatePHY packet 240. The aggregate PHY packet 240 includes a PHY preamble 228including an STF 234 and an LTF 236. Following the preamble 228 arethree (although fewer or more than three are possible) PHY payloads 232,each one of which is preceded by a corresponding PHY header 230including a SIG 238. Each of the PHY payloads 232 includes an aggregateMAC packet 216. As explained above, each MAC packet 210 in an aggregateMAC packet 216 is delivered to the same receiving node. However, each ofthe PHY layer payloads 232 in the aggregate PHY packet 240 may betransmitted to the same or different receiving nodes. The SIG 238 isprovided before each PHY layer payload 232 to allow each aggregate MACpacket 216 to be transmitted at a different data rate. However, only onePHY layer preamble 228 is required for the entire aggregate PHY packet240. Hence, only one PHY layer preamble 228 is required for multipleaggregate MAC packets 216, even if they are being transmitted todifferent receiving nodes. All receiving nodes can estimate the channel,synchronize and calculate the AGC gain using one preamble. Combining PHYlayer payloads in an aggregate PHY packet allows for removal of interframe spacing between aggregate MAC packets as well as aggregation ofthe preambles (training fields) for multiple aggregate MAC packets.

Although FIG. 2 shows one aggregate MAC packet per PHY layer payload,each PHY layer payload may include more than one aggregate MAC packet.Alternatively, one or more aggregate MAC packets may be fragmented anddistributed over more than one PHY layer payload.

As will be discussed in greater detail later, the PHY layer 206 is alsoresponsible for providing various signal processing functions (e.g.,modulating, coding, spatial processing, etc.).

When the wireless node is in a receive mode, the process described aboveis reversed. That is, the PHY layer 206 detects an incoming aggregatePHY packet 240 from the wireless channel. The preamble 228 allows thePHY layer 206 to lock in on the aggregate PHY packet 240 and performvarious signal processing functions (e.g., demodulating, decoding,spatial processing, etc.). Once processed, the PHY layer 206 recoversthe aggregate MAC packets 216 carried in the payloads 232 of theaggregate PHY packet 240 and provides the aggregate MAC packets 216 tothe MAC layer 204.

The MAC layer 204 recovers the aggregate MAC packets 216 with the sourceaddress for the receiving node in one or more of the MAC headers 214.The MAC layer 204 then checks the error detection code for each of theMAC packets 210 in the recovered aggregate MAC packets 216 to determinewhether it was successfully decoded. If the error detection code for aMAC packet 210 indicates that it was successfully decoded, then thepayload 212 for the MAC packet is provided to the application layer 202.If the error detection code for a MAC packet 210 indicates that it wasunsuccessfully decoded, the MAC packet 210 is discarded.

In order to determine whether MAC packets 210 in an aggregate MAC packet216 were received and decoded successfully, the transmitting node maysend an acknowledgment (ACK) request to the receiving node. The ACKrequest may take the form of a Block ACK Request (BAR) which requeststhe receiving node to acknowledge every MAC packet 210 transmitted inthe aggregate MAC packet 216. In response to a BAR, the receiving noderesponds with a Block ACK (BA) indicating which MAC packets 210 in theaggregate MAC packet 216 were successfully decoded. The transmittingnode uses the BA to determine which MAC packets 210, if any, requireretransmission.

Alternatively, the transmitting node (labeled as AP 100 in the exampledescribed below with respect to FIG. 3) can specify a schedule of BAsfor all receiving nodes. By way of example, as shown in FIG. 3, anaggregate PHY packet may be configured to carry a schedule for the BAsin one of the PHY payloads 232 a. The schedule may be provided to eachreceiving node (labeled as ATs 101-110 in FIG. 3) with a channeldesignation for transmitting the BA. The channel designation may includetransmission time, frequency channel, code channel, and/or some othersuitable or desirable channel designation. In one configuration of awireless network, the channel designation is a schedule of transmissiontimes for the receiving nodes to send back BAs to the transmitting node.This schedule will be referred to herein as a Block ACK Time Assignment(BATA). The BATA carried in the PHY payload 232 a is preceded by the PHYpreamble 228 of the aggregate PHY packet 240 and a header 230 a directedto the BATA. The header 230 a may include a designation indicating adata rate for transmission of the BATA. The BATA is transmitted to eachnode receiving an aggregate MAC packet carried in the payload 232 of theaggregate PHY packet 240 and includes a schedule of Block ACK channeldesignations for each station. In response to the BATA, each receivingnode sends a BA back to the transmitting node at its scheduled time. Byincluding the BATA in the aggregate PHY packet 240, it is not necessaryfor the transmitting node to send a separate BAR to each receiving node,thereby reducing overhead and transmission time, and eliminatinginter-frame spacing between BARs that might otherwise be required.

In some configurations of a node, a Data Transmission Time (DTT)schedule may be transmitted to each receiving node. The DTT may beincluded as the first PHY payload in the aggregate PHY packet. By way ofexample, FIG. 4 shows a DTT in the payload 232 b of an aggregate PHYpacket 240. The DTT follows the PHY preamble 228 and includes a header230 b comprising a SIG indicating a data rate for transmission of theDTT. The DTT includes a DTT Table, which includes the receiving nodesfor the aggregate PHY packet 240, a node identification (NodeID) fieldidentifying each receiving node with a unique NodeID and a datatransmission time field including a unique transmission time for eachreceiving node identified in the NodeID field. By knowing when to expecta transmission, it is possible for each receiving node to power downmost functions (i.e., “go to sleep”) until it is time to receive atransmission, thereby achieving significant power savings.

In some configurations of a node, the BATA can be a PHY packet, ordistributed as part of MAC packets, while the DTT may be transmitted asa PHY payload in the aggregate PHY packet.

FIG. 5 is a conceptual block diagram illustrating an example of thesignal processing functions of the PHY layer. In a transmit mode, a TXdata processor 502 may be used to receive data from the MAC layer andencode (e.g., Turbo code) the data to facilitate forward errorcorrection (FEC) at the receiving node. The encoding process results ina sequence of code symbols that that may be blocked together and mappedto a signal constellation by the TX data processor 502 to produce asequence of modulation symbols.

In wireless nodes implementing OFDM, the modulation symbols from the TXdata processor 502 may be provided to an OFDM modulator 504. The OFDMmodulator splits the modulation symbols into parallel streams. Eachstream is then mapped to an OFDM subcarrier and then combined togetherusing an Inverse Fast Fourier Transform (IFFT) to produce a time domainOFDM stream.

A TX spatial processor 506 performs spatial processing on the OFDMstream. This may be accomplished by spatially precoding each OFDM andthen providing each spatially precoded stream to a different antenna 508via a transceiver 506. Each transmitter 506 modulates an RF carrier witha respective precoded stream for transmission over the wireless channel.

In a receive mode, each transceiver 506 receives a signal through itsrespective antenna 508. Each transceiver 506 may be used to recover theinformation modulated onto an RF carrier and provide the information toa RX spatial processor 510.

The RX spatial processor 510 performs spatial processing on theinformation to recover any spatial streams destined for the wirelessnode 500. The spatial processing may be performed in accordance withChannel Correlation Matrix Inversion (CCMI), Minimum Mean Square Error(MMSE), Soft Interference Cancellation (SIC), or some other suitabletechnique. If multiple spatial streams are destined for the wirelessnode 500, they may be combined by the RX spatial processor 510.

In wireless nodes implementing OFDM, the stream (or combined stream)from the RX spatial processor 510 is provided to an OFDM demodulator512. The OFDM demodulator 512 converts the stream (or combined stream)from time-domain to the frequency domain using a Fast Fourier Transform(FFT). The frequency domain signal comprises a separate stream for eachsubcarrier of the OFDM signal. The OFDM demodulator 512 recovers thedata (i.e., modulation symbols) carried on each subcarrier andmultiplexes the data into a stream of modulation symbols.

A RX data processor 514 may be used to translate the modulation symbolsback to the correct point in the signal constellation. Because of noiseand other disturbances in the wireless channel, the modulation symbolsmay not correspond to an exact location of a point in the originalsignal constellation. The RX data processor 514 detects which modulationsymbol was most likely transmitted by finding the smallest distancebetween the received point and the location of a valid symbol in thesignal constellation. These soft decisions may be used, in the case ofTurbo codes, for example, to compute a Log-Likelihood Ratio (LLR) of thecode symbols associated with the given modulation symbols. The RX dataprocessor 514 then uses the sequence of code symbol LLRs in order todecode the data that was originally transmitted before providing thedata to the MAC layer.

FIG. 6 is a conceptual diagram illustrating an example of a hardwareconfiguration for a processing system in a wireless node. In thisexample, the processing system 600 may be implemented with a busarchitecture represented generally by bus 602. The bus 602 may includeany number of interconnecting buses and bridges depending on thespecific application of the processing system 600 and the overall designconstraints. The bus links together various circuits including aprocessor 604, machine-readable media 606, and a bus interface 608. Thebus interface 608 may be used to connect a network adapter 610, amongother things, to the processing system 600 via the bus 602. The networkadapter 610 may be used to implement the signal processing functions ofthe PHY layer. In the case of an access terminal 110 (see FIG. 1), auser interface 612 (e.g., keypad, display, mouse, joystick, etc.) mayalso be connected to the bus. The bus 602 may also link various othercircuits such as timing sources, peripherals, voltage regulators, powermanagement circuits, and the like, which are well known in the art, andtherefore, will not be described any further.

The processor 604 is responsible for managing the bus and generalprocessing, including the execution of software stored on themachine-readable media 606. The processor 604 may be implemented withone or more general-purpose and/or special-purpose processors. Examplesinclude microprocessors, microcontrollers, DSP processors, and othercircuitry that can execute software. Software shall be construed broadlyto mean instructions, data, or any combination thereof, whether referredto as software, firmware, middleware, microcode, hardware descriptionlanguage, or otherwise. Machine-readable media may include, by way ofexample, RAM (Random Access Memory), flash memory, ROM (Read OnlyMemory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program products The computer-program product may comprisepackaging materials.

In the hardware implementation illustrated in FIG. 6, themachine-readable media 606 is shown as part of the processing system 600separate from the processor 604. However, as those skilled in the artwill readily appreciate, the machine-readable media 606, or any portionthereof, may be external to the processing system 600. By way ofexample, the machine-readable media 606 may include a transmission line,a carrier wave modulated by data, and/or a computer product separatefrom the wireless node, all which may be accessed by the processor 604through the bus interface 608. Alternatively, or in addition to, themachine readable media 606, or any portion thereof, may be integratedinto the processor 604, such as the case may be with cache and/orgeneral register files.

The processing system 600 may be configured as a general-purposeprocessing system with one or more microprocessors providing theprocessor functionality and external memory providing at least a portionof the machine-readable media 606, all linked together with othersupporting circuitry through an external bus architecture.Alternatively, the processing system 600 may be implemented with an ASIC(Application Specific Integrated Circuit) with the processor 604, thebus interface 608, the user interface 612 in the case of an accessterminal), supporting circuitry (not shown), and at least a portion ofthe machine-readable media 606 integrated into a single chip, or withone or more FPGAs (Field Programmable Gate Array), PLDs (ProgrammableLogic Device), controllers, state machines, gated logic, discretehardware components, or any other suitable circuitry, or any combinationof circuits that can perform the various functionality describedthroughout this disclosure. Those skilled in the art will recognize howbest to implement the described functionality for the processing system600 depending on the particular application and the overall designconstraints imposed on the overall system.

The machine-readable media 606 is shown with a number of softwaremodules.

The software modules include instructions that when executed by theprocessor 604 cause the processing system 600 to perform variousfunctions. The software modules include a transmission module 700 and areceiving module 800. Each software module may reside in a singlestorage device or distributed across multiple storage devices. By way ofexample, a software module may be loaded into RAM from a hard drive whena triggering event occurs. During execution of the software module, theprocessor 604 may load some of the instructions into cache to increaseaccess speed. One or more cache lines may then be loaded into a generalregister file for execution by the processor 604. When referring to thefunctionality of a software module below, it will be understood thatsuch functionality is implemented by the processor 604 when executinginstructions from that software module.

FIG. 7 is a flow chart illustrating an example of the functionality ofthe transmission module. The transmission module 700 may be used toobtain data packets from the application layer (S702), assemble the datapackets into MAC packets by fragmenting and/or concatenating datapackets and appending a MAC header to each MAC packet (S704), as shownin FIG. 2. The transmission module 700 may embed a BATA in one or moreof the MAC packets, such as in one or more of the MAC packet headers(S706). As also shown in FIG. 2, the transmission module 700 generatesmultiple subframes by appending a subframe header to each of the MACpackets and packaging the subframes into aggregate MAC packets (S708).The transmission module 700 sends the aggregated MAC packets to the PHYlayer (S710).

The PHY layer receives the aggregated MAC packets (S712) and may be usedto package multiple aggregated MAC packets into an aggregate PHY packetby: optionally fragmenting and/or concatenating aggregated MAC packets;combining aggregated MAC packets (including fragments if appropriate)into one or more PHY payloads (S714); appending a PHY layer header toeach PHY payload (S716); and appending a preamble to the beginning ofthe aggregated PHY packet (S718). If the BATA is not embedded in one ormore of the MAC packets, the transmission module 700 may include theBATA as a payload of the aggregated PHY packet and append a header tothe PHY payload carrying the BATA (S720). The transmission module 700may also add a DTT as a separate PHY payload following the PHY preamble,and append a header to the PHY payload carrying the DTT (S720). Thetransmission module 700 then provides the aggregated PHY packet to thebus interface 608 for delivery to the network adaptor 610 fortransmission over the wireless channel (see FIG. 6). If included, theDTT may be the first payload of the PHY packet.

FIG. 8 is a flow chart illustrating an example of the functionality ofthe receiving module. The software module 800, as shown in FIG. 8, maybe used to receive aggregate PHY packets including a BATA from thenetwork adapter 610 via the bus interface 608 (see FIG. 6) (S802). Themodule 800 checks to see whether a DTT has been received (S804). If aDTT has been received (as shown in FIG. 4, for example), the module 800reserves resources by going to sleep until the scheduled time to receivea transmission (S806). At the scheduled time, the module 800 decodes thereceived aggregate PHY packets and performs error detection on the MACpackets in the aggregated PHY packets addressed to the receiving node(S808). The module 800 then waits until the allotted time indicated inthe BATA (S810) and sends a BA to the network adaptor 610 (see FIG. 6)at the allotted time, as shown in FIG. 3 (S812).

FIG. 9 is a block diagram illustrating an example of the functionalityof an apparatus for communication 900 according to an embodiment of theinvention. The apparatus includes a processing system having a module902 for generating a physical layer packet for transmission to a node,the physical layer packet including a transmission schedule associatedwith a plurality of MAC packets in the physical layer packet, and amodule 904 for providing the plurality of MAC packets in the physicallayer packet.

FIG. 10 is a block diagram illustrating an example of the functionalityof an apparatus for communication 1000 according to another embodimentof the invention. The apparatus includes a processing system having amodule 1002 for receiving a data packet from a node, including atransmission schedule associated with a plurality of MAC packets in aphysical layer packet, and a module 1004 for providing the plurality ofMAC packets in the physical layer packet.

It is understood that any specific order or hierarchy of steps describedin the context of a software module is being presented to provide anexample of a wireless node. Based upon design preferences, it isunderstood that the specific order or hierarchy of steps may berearranged while remaining within the scope of the invention.

Although various aspects of the invention have been described assoftware implementations, those skilled in the art will readilyappreciate that the various software modules presented throughout thisdisclosure may be implemented in hardware, or any combination ofsoftware and hardware. Whether these aspects are implemented in hardwareor software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the invention.

The previous description is provided to enable any person skilled in theart to fully understand the full scope of the invention. Modificationsto the various configurations disclosed herein will be readily apparentto those skilled in the art. Thus, the claims are not intended to belimited to the various aspects of the invention described herein, but isto be accorded the full scope consistent with the language of claims,wherein reference to an element in the singular is not intended to mean“one and only one” unless specifically so stated, but rather “one ormore.” Unless specifically stated otherwise, the term “some” refers toone or more. All structural and functional equivalents to the elementsof the various aspects described throughout this disclosure that areknown or later come to be known to those of ordinary skill in the artare expressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims. No claim element is tobe construed under the provisions of 35 U.S.C. §112, sixth paragraph,unless the element is expressly recited using the phrase “means for” or,in the case of a method claim, the element is recited using the phrase“step for.”

1. An apparatus for communication, comprising: a processing systemconfigured to generate a physical layer packet for transmission to anode, the physical layer packet having a plurality of MAC packets,wherein the physical layer packet includes a transmission scheduleassociated with the plurality of MAC packets in the physical layerpacket.
 2. The apparatus of claim 1 wherein the transmission schedulecomprises a transmission schedule for each of the MAC packets from theapparatus.
 3. The apparatus of claim 1 wherein the transmission schedulecomprises a transmission schedule for one or more responses to the MACpackets from the node.
 4. The apparatus of claim 3 wherein the one ormore responses comprise a block acknowledgement to the MAC packets. 5.The apparatus of claim 3 wherein the one or more responses comprise anacknowledgement to each of the MAC packets.
 6. An apparatus forcommunication, comprising: a processing system configured to receive aphysical layer packet from a node, the physical layer packet having aplurality of MAC packets, wherein the physical layer packet includes atransmission schedule associated with the plurality of MAC packets inthe physical layer packet.
 7. The apparatus of claim 6 wherein thetransmission schedule comprises a transmission schedule for each of theMAC packets from the node.
 8. The apparatus of claim 6 wherein thetransmission schedule comprises a transmission schedule for one or moreresponses to the MAC packets from the apparatus.
 9. The apparatus ofclaim 8 wherein the one or more responses comprise a blockacknowledgement to the MAC packets.
 10. The apparatus of claim 8 whereinthe one or more responses comprise an acknowledgement to each of the MACpackets.
 11. The apparatus of claim 8 wherein the processing system isfurther configured to sleep during a period of time between theprocessing system receiving the MAC packets and the transmission timefor transmitting the one or more responses from the apparatus.
 12. Amethod of communication, comprising: generating a physical layer packetfor transmission to a node, the physical layer packet having a pluralityof MAC packets, wherein the physical layer packet includes atransmission schedule associated with the plurality of MAC packets inthe physical layer packet.
 13. The method of claim 12 wherein thetransmission schedule comprises a transmission schedule for each of theMAC packets from the method.
 14. The method of claim 12 wherein thetransmission schedule comprises a transmission schedule for one or moreresponses to the MAC packets from the node.
 15. The method of claim 14wherein the one or more responses comprises a block acknowledgement tothe MAC packets.
 16. The method of claim 14 wherein the one or moreresponses comprises an acknowledgement to each of the MAC packets.
 17. Amethod of communication, comprising: receiving a physical layer packetfrom a node, the physical layer packet having a plurality of MACpackets, wherein the physical layer packet includes a transmissionschedule associated with the plurality of MAC packets in the physicallayer packet.
 18. The method of claim 17 wherein the transmissionschedule comprises a transmission schedule for each of the MAC packetsfrom the node.
 19. The method of claim 17 wherein the transmissionschedule comprises a transmission schedule for one or more responses tothe MAC packets from the method.
 20. The method of claim 19 wherein theone or more responses comprises a block acknowledgement to the MACpackets.
 21. The method of claim 19 wherein the one or more responsescomprises an acknowledgement to each of the MAC packets.
 22. The methodof claim 19 further comprising sleeping during a period of time betweenthe receiving of MAC packets and the transmission time for transmittingthe one or more responses.
 23. An apparatus for communication,comprising: means for generating a physical layer packet fortransmission to a node; and means for providing a plurality of MACpackets in the physical layer packet; wherein the physical layer packetincludes a transmission schedule associated with the plurality of MACpackets in the physical layer packet.
 24. The apparatus of claim 23wherein the transmission schedule comprises a transmission schedule foreach of the MAC packets from the apparatus.
 25. The apparatus of claim23 wherein the transmission schedule comprises a transmission schedulefor one or more responses to the MAC packets from the node.
 26. Theapparatus of claim 25 wherein the one or more responses comprise a blockacknowledgement to the MAC packets.
 27. The apparatus of claim 25wherein the one or more responses comprise an acknowledgement to each ofthe MAC packets.
 28. An apparatus for communication, comprising: meansfor receiving a physical layer packet from a node; and means forproviding a plurality of MAC packets in the physical layer packet;wherein the physical layer packet includes a transmission scheduleassociated with the plurality of MAC packets in the physical layerpacket.
 29. The apparatus of claim 28 wherein the transmission schedulecomprises a transmission schedule for each of the MAC packets from thenode.
 30. The apparatus of claim 28 wherein the transmission schedulecomprises a transmission schedule for one or more responses to the MACpackets from the apparatus.
 31. The apparatus of claim 30 wherein theone or more responses comprise a block acknowledgement to the MACpackets.
 32. The apparatus of claim 30 wherein the one or more responsescomprise an acknowledgement to each of the MAC packets.
 33. Theapparatus of claim 30 further comprising means for sleeping during aperiod of time between the receiving of MAC packets and the transmissiontime for transmitting the one or more responses.
 34. A computer-programproduct for communication, comprising: a machine-readable medium encodedwith instructions executable to: generate a physical layer packet fortransmission to a node, the physical layer packet having a plurality ofMAC packets, wherein the physical layer packet includes a transmissionschedule associated with the plurality of MAC packets in the physicallayer packet.
 35. A computer-program product for communication,comprising: a machine-readable medium encoded with instructionsexecutable to: receive a physical layer packet from a node, the physicallayer packet having a plurality of MAC packets, wherein the physicallayer packet includes a transmission schedule associated with theplurality of MAC packets in the physical layer packet.
 36. An accesspoint, comprising: a processing system configured to generate a physicallayer packet for transmission to a node, the physical layer packethaving a plurality of MAC packets, wherein the physical layer packetincludes a transmission schedule associated with the plurality of MACpackets in the physical layer packet; and a wireless network adapterconfigured to support a backhaul connection for a peer node to anetwork.
 37. An access terminal, comprising: a processing systemconfigured to receive a physical layer packet from a node, the physicallayer packet having a plurality of MAC packets, wherein the physicallayer packet includes a transmission schedule associated with theplurality of MAC packets in the physical layer packet; and a userinterface supported by the processing system.